The present invention relates to a method of modifying the command set of a smart card. More particularly, the present invention relates to a method of modifying individual command of a smart card.
A smart card, also called an IC card (IC=Integrated Circuit), is an electronic device for making payments. The integrated circuit of the card contains a microprocessor or the like for processing data. The processor of a smart card is normally provided with a command set comprising commands (such as Read, Write, Update, etc. for operating upon the (payment) data contained in the card. Often standardized commands are used, such as e.g. defined by European Norm EN726. However, such command set is necessarily limited with respect to the number and the scope of the commands. As electronic payment systems involving smart cards develop, the need often arises to add new functions to the card, or to alter existing functions. Such changes usually imply a modification of the command set of the smart card. This would normally involve a redesign of the integrated circuit of the card, which is not only expensive but renders existing cards obsolete. Furthermore, altering a standardized command set would jeopardize its compatibility with the standard.
For these and other reasons, the need arises to be able to modify the command set of smart cards without substantially deviating from the existing set of commands.